The Modular Sealing Washer System is an adaptive mill sealing system for liner bolt holes, available in two standard sizes and one oversize option. This range in sizing options provides the versatility necessary to allow mill mechanics to select the appropriate seal based on the condition of their mills.
Over time, liner mounting holes become elongated and enlarged, which creates opportunities for slurry leakage.
Why Do Mill Liner Bolt Holes Leak Over Time?
Even with proper installation, several mechanisms are working against a perfect seal:
- Cyclic loading & vibration – Mills experience constant impact and shell flexing, which can relax bolt preload and break down sealing interfaces.
- Wear and erosion – Slurry is extremely abrasive, causing any exposed gaps around bolts, washers, or sleeves to slowly erode and increase leak paths.
- Bolt preload loss – Thermal cycling, liner wear, and settling all have an impact on clamp force. Once a preload drops below a critical level, slurry will infiltrate.
- Corrosion – Corrosion under washers or sleeves can create capillary paths, especially in acidic or chloride-rich slurries.
- Installation variability – Even the smallest of inconsistencies in torque, surface cleanliness, or alignment can shorten the seal life.
Despite these factors, good design and maintenance can prevent leakage and extend the seal life of each bolt hole. This is why modern mills are increasingly focused on bolt load verification, improved sealing assemblies, and predictive maintenance rather than reactive slurry cleanup.
How to Stop Slurry Leakage in Mill Liner Bolt Holes with a Modular Sealing Washer System
As mill diameters increase, a higher load is required to keep liners in place; some liner manufacturers require up to 200,000 pounds of bolt preload for larger SAG mills. These high load amounts can prematurely deform the steel retaining washer, which is why Valley Forge & Bolt engineered our new Modular Sealing Washer System to withstand more than 225,000 pounds of load without plastic deformation. Our washer is also strategically forged instead of cast, which is much better-suited to withstand higher loads. Lister washers and other cast washers found in the field have created many of the problems that our Modular Sealing Washer System now solves.
Relining your mill takes valuable time, and any inefficiencies in the process will cost you production time and, ultimately, revenue. Every process improvement in your mill environment equates to more operating hours each year. Our system is configurable to provide a solution for your sealing needs regardless of the condition of the liner mounting holes, and is designed to easily handle the highest load values specified by the OEM and liner manufacturers.
Let us help!
Are you experiencing issues with slurry leakage in your mill liner or a loss of load from washer deformation? Let us help! We’d like to offer you some modular sealing washer sets to test at your mill processing site. Simply fill out the form below and our team will respond with the next steps!
